Design Modification of Greenhouse Effect Solar-Hybrid Rack Type Dryer

Abstract

Hybrid solar-type rack dryers are modified to improve efficiency and to save the drying energy. Modifications are made to the main components, namely; furnace and heat exchanger. The dimension of dryer was 1.8 m length, 0.7 m width and 1.8 m high. The dryer was equipped by 22 racks with dimension of 0.5 m x 0.65m. The furnace was modified to a cylindrical shape instead of rectangular shape and was designed with optimization of heat utilization and comfortable to be operated. To reduce heat loss, the wall of furnace was designed contact directly the drying room. The furnace material was iron galvanized plate with a thickness of 2 mm. The foregoing design of heat exchanger was tube bank type with horizontal fins attached on tubes. In this research, the adoption of vertical fins has enlarged the heat transfer area and increase the effectiveness of heat exchanger. The smoke flow from the combustion chamber of furnace was directed at the opposite side of the ambient air inlet for drying, so that smoke does not enter the drying chamber.